title: Antibiotic principle of Eupatorium capillifolium.
abstract: Ethanolic extracts of Eupatorium capillifolium (Lam) Small showed activity against Bacillus subtilis grown in a chemically defined medium but not in a complex natural medium. The active principle was isolated as a colorless crystalline solid. A study of its properties and mass spectral fragmentation pattern showed that it was costic acid, a sesquiterpenic acid previously isolated from Costus root oil. The observed inactivity of costic acid against B. subtilis in a complex medium was shown to be due to the presence in the medium of glutamic acid, which is capable of reversing 90% of the activity of costic acid.
mesh_terms: D000900:Anti-Bacterial Agents / Q000302:isolation & purification*; D001412:Bacillus subtilis / Q000187:drug effects; D055598:Chemical Phenomena; D002621:Chemistry; D010936:Plant Extracts / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts